This application relates generally to capacitors, and more specifically to capacitors having a plurality of electrodes.
Capacitors are used in integrated circuits to store and supply electrical charge. Capacitors include conductive electrodes (sometimes referred to as plates) that are separated by dielectrics and store electrostatic charges. The charge Q is directly related to the product of capacitance C and voltage V, i.e., Q=CV. Capacitance is directly proportional to the area of either electrode A and to the dielectric constant (∈) of the media separating the electrodes, and inversely proportional to the distance between the electrodes d: C=∈A/4xcfx80d. Accordingly, capacitance can be desirably increased by increasing the area of the electrodes, increasing the dielectric constant, or deceasing the distance between the electrodes.
Capacitors are typically found at an interface between an integrated circuit and other integrated circuits and other systems. A specific application of capacitors is in a voltage stabilizer that maintains an applied voltage in the event of a voltage fluctuation at the interface. Today""s integrated circuits operate at ever faster speeds. Accordingly, a capacitor must efficiently and quickly supply its stored charge to maintain the voltage level during such a fluctuation. However, capacitors in addition to storing charge have a small effective inductance and resistance. Such an inductance is called equivalent series inductance (xe2x80x9cESLxe2x80x9d) or parasitic inductance. A capacitor must have a low ESL to quickly supply its charge, especially at high frequencies (fast operating speeds). Moreover, in some electrical devices, such as devices with high performance processors, capacitors may have different ESL or equivalent series resistance (xe2x80x9cESRxe2x80x9d) depending on the capacitor""s length-height or length-width orientation. Improper capacitor orientation may result in failure of the device. Accordingly, it is desirable to provide a capacitor having a low ESL and a capacitor having characteristics that are not dependent on the capacitor""s orientation.